Loss of biventricular capture related to a dysfunction of the right ventricular lead

Patient

79-year-old man implanted with a triple-chamber defibrillator Consulta XT CRT-D for ischemic cardiomyopathy with a wide QRS (the device was implanted 8 years ago and already replaced once); the consultation is motivated by several electrical shocks received while he was working in his garden.

Trace

Plots:

scattered distribution at the ventricular level (great variability in cycle lengths with very short intervals);
electrical cardioversion;
short ventricular cycles;
end of the oversensing;

Tracing:

ventricular oversensing of anarchic signals in the VT and VF zones;
intermittent biventricular pacing;
spontaneous ventricular activities;
NID in the VF zone is reached; detection of a VF episode and charging of the capacitors;
end of charge (CE);
confirmation: 4 consecutive VS, the therapy is abandoned;
new detection of a VF and new charge of the capacitors;
end of charge (very short, the capacitors had no time to discharge);
no confirmation for this redetected episode; immediate delivery of an electrical shock (34.3 Joules);
temporary interruption of the oversensing and biventricular pacing;
new episode of oversensing;
end of the episode.

Comments

This patient, initially implanted for primary prevention in the context of a severe heart failure, presented with a fracture of the right ventricular lead. He could be considered as a good clinical and echocardiographic responder to CRT. No episode of arrhythmia was recorded in the memories of the device. Regarding the diagnosis of lead fracture, different options are possible. The easiest would probably be to disable the defibrillation function of the device to prevent any recurrence of inappropriate therapies while maintaining a biventricular pacing. However, this tracing shows the limits of this strategy since the oversensing also inhibits biventricular pacing. It is likely that with the progression of the lead problem, the oversensing will increase and result in a significant drop in the percentage of biventricular pacing. A second option is to add a new defibrillation lead (this option was chosen in this patient) or a right ventricular pacing lead. The management of the former broken lead was difficult. It was left in place in the patient. Indeed, its extraction was probably not justified in a patient of this age, especially if we consider the associated risk of damaging the left ventricular functional lead.

Pacing & Defibrillation

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